Enhancing antifogging/frost-resisting performances of amphiphilic coatings via cationic, zwitterionic or anionic polyelectrolytes

Polymeric antifogging and frost-resisting coatings were successfully prepared, but the performances of amphiphilic coatings containing different kinds of cationic, zwitterionic and anionic polyelectrolytes are still needed to investigate systematically. In this work, antifogging/frost-resisting coatings with high transparence were developed from amphiphilic copolymers of cationic, zwitterionic or anionic poly(2-(dimethylamino)ethyl methacrylate (DMAEMA)-co-2,2,2-trifluoroethyl methacrylate (FMA))-b-polyelectrolytes with a small amount of ethylene glycol dimethacrylate via UV-curing. Studies on the prepared amphiphilic coatings suggested that the cationic and zwitterionic coatings exhibited superior antifogging properties, whereas the anionic polyelectrolyte-based coating demonstrated a better frost-resisting behavior. Water molecule activities in the amphiphilic coatings were analyzed by differential scanning calorimetry, Raman spectroscopy and low field nuclear magnetic resonance. It was found that the cationic and zwitterionic coatings containing 2-(methacryloyloxy)-ethyltrimethyl ammonium chloride and sulfobetaine methacrylate, respectively, exhibited stronger polymer-water interactions dominated by strong hydrogen bonds, and held more nonfreezable water content with shorter transverse spin-spin relaxation time T-2 than the anionic coating containing 3-sulfopropyl methacrylate potassium (SPMA). Electrostatic interactions between anionic SPMA and DMAEMA units in the copolymer could weaken the polymer-water interaction, leading to a compromise in the antifogging performance and an enhancement of frost-resisting ability of the coating. The results of this study would be applicable for exploring the advanced antifogging/frost-resisting coatings.